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Focal accumulation of fluorodeoxyglucose (FDG) into the thyroid is detected in 4% of patients examined for nonthyroid tumors by positron emission tomography (PET) imaging. Up to 40% of these patients have malignant tumors, mainly arising from follicular cells (1). Benign nodules (i.e. follicular adenomas) may accumulate FDG also, but FDG-negative nodules are very unlikely to be malignant (2, 3). Langherans cell histiocytosis (LCH) is a rare monoclonal disease of histiocytes with an overall 3% mortality in adults, rarely involving the thyroid gland alone or as part of multisystemic disease (4). We observed a 43-yr-old female affected by breast carcinoma with an incidentally discovered thyroid enlargement. Clinical examination revealed a 20-mm hard nodule in the left thyroid lobe. Serum TSH was normal and ultrasoundguided fine-needle aspiration biopsy was directly performed by a dedicated cytopathologist (21-gauge needle, three passes). The cytological examination showed few thyrocytes without malignant findings, some lymphocytes and macrophages, and was classified as nondiagnostic (thy1) according to the British Thyroid Association 2002 recommendations. The role of fineneedle aspiration biopsy repetition in these cases is debated and, based on its high negative predictive value for both thyroid and breast carcinomas, an 18FDG-PET/computed tomography scan was performed (5, 6). A focal FDG uptake was shown in the left thyroid nodule (SUVmax 8.45) (Fig. 1) without other pathological FDG-positive areas. Left lobectomy was then performed, and thyroid LCH was demonstrated by histological examination and immunostaining against S-100 protein. Thyroid involvement by LCH is rare, and the diagnosis may often be extremely difficult (7). Neither ultrasound nor scintigraphy provides specific findings for LCH, and the final diagnosis is generally reached through cytological or histological examination (8). The high FDG uptake found in the present case reflected the enhanced metabolic rate of LCH cells. Clearly, FDG uptake is not specific for LCH; however, according to recently reported data, malignant disease should be excluded in FDGpositive thyroid nodules (9). To our knowledge, we first reported here the FDG uptake by LCH; this is of interest for nuclear medicine physicians involved in PET imaging and, additionally, may suggest further evaluations of FDG imaging in LCH assessment.

OBJECTIVE: To evaluate the influence of family history of hypertension on insulin sensitivity in obese normotensive adults, comparing them with lean subjects. SUBJECTS: 136 normotensives (N)(mean 24 h blood pressure

The aim of this study was the evaluation of the relationships among hyperinsulinemia, a family history of hypertension, and essential hypertension. Insulin and C-peptide responses to an oral glucose load were studied in 175 lean normotensives (N) and untreated hypertensives (H) with (F+) and without (F−) a family history of hypertension: 30 NF-, 30 NF+, 45 HF-, and 70 HF+. The groups were comparable for age, sex, body mass index, and blood pressure. The following parameters were evaluated: plasma glucose (G), serum insulin (I), and C-peptide (Cp) before and 30, 60, 90, and 120 min after the glucose load, fasting glucose/insulin ratio (ISI), fasting insulin/C-peptide ratio (I/Cp), and 24-h ambulatory blood pressure monitoring. Plasma glucose was measured, fasting and during the test, and it and I/Cp were similar in the four groups. Serum insulin and Cp, both fasting and stimulated, were significantly higher and ISI lower in normotensives and hypertensives with hypertensive parents. Grouping the subjects first on the basis of blood pressure and then on the basis of family history, no differences were found between normotensives and hypertensives, whereas I and Cp, fasting and stimulated, were significantly higher and ISI lower in subjects with positive as compared to negative family history. The closest correlations between insulin and ambulatory blood pressure were found in normotensives with hypertensive parents; in hypertensives with hypertensive parents we only found a direct correlation between fasting Cp and nocturnal blood pressure fall; in hypertensives with normotensive parents insulin inversely correlated with nocturnal blood pressure fall. Insulin resistance seems to have a familial basis, independently of the presence of hypertension. Instead of showing a causal relationship between insulin resistance and hypertension, our results indicate that the two are partly independent components of a common familial pattern.

Abstract 1566 Background. Response-tailored management of PMLBCL is a major challenge in everyday practice, mostly due to the persistence of post-treatment residual masses of uncertain nature. PET/CT is now widely used in the definition of response and as a prognostic indicator, in Hodgkin lymphoma (HL) and diffuse large B cell lymphoma (DLBCL), while its role in patients with PMLBCL remains to be defined. Aim of the study. The IELSG-26 study was designed to prospectively evaluate the clinical role of PET/CT after rituximab and anthracycline-containing immunochemotherapy (R-CHT) in patients with PMLBCL. Methods. Between January 2007 and July 2010, 125 patients (pts) with PMLBCL were enrolled in 21 institutions and treated with R-CHOP-like (20 pts), R-VACOP-B (34 pts) or R-MACOP-B (71 pts) regimens according to the local policy; consolidation with mediastinal involved field radiotherapy (IFRT) as indicated by local guidelines was allowed. PET/CT scans were planned at baseline, at 3–4 weeks after R-CHT and at 12 weeks after radiotherapy. Central PET/CT review was performed at the end of treatment using the Deauville score (Meignan et al. Leuk Lymphoma 2009) and complete response (CR) was defined as a negative PET scan or one having minimal residual uptake lower than mediastinal blood pool (MBP) activity in regions which were FDG-PET positive at baseline according to the criteria of the International Harmonization Project in Lymphoma (Juweid et al. JCO 2007). Results. Treatment was administered as initially planned in 119 pts (including IFRT in 106); there were 6 early withdrawals (4 with early progression and 2 with stable disease receiving second-line chemotherapy). PET imaging was not done (n=2) or not evaluable due to technical problems (n=2) in 4 pts, therefore, central review of PET/CT was possible in 115/119 patients. PET/CT visual assessment at 3–4 weeks post-R-CHT showed metabolic CR in 54/115 patients (47%; 95% CI, 36%–56%): in 12 cases (10%; 95% CI, 6%–18%) PET/CT scan was completely negative (score 1 according to the Deauville criteria), while in 42 (37%; 95% CI, 28%–46%) there were small residual masses with an uptake less than MBP (score 2). PET/CT scans showed a positive residual mass after R-CHT in 61/115 pts (53%; 95% CI, 44%–62%). The residual uptake was higher than MBP but below the liver uptake (score 3) in 27 pts (23%; 95% CI, 16%–32%), slightly higher than the liver uptake (score 4) in 24 pts (21%; 95% CI, 14%–29%) and markedly higher than the liver uptake (score 5) in 10 pts (9%; 95% CI, 4%–15%). Despite only 47% of patients attaining a CR -defined by the uptake below MBP activity- after R-CHT, at a median follow-up of 2.8 years, the estimated 5-year overall survival (OS) and progression-free survival (PFS) rates were 96% (95% CI, 89%–98%) and 91% (95% CI, 84%–95%), respectively. The achievement of a CR at 3–4 weeks after R-CHT predicted a longer PFS (p=0.015) with high sensitivity but poor specificity (negative predictive value of 0.98 but positive predictive value of only 0.15) and showed a borderline impact (p=0.052) on OS. Patients with Deauville score 3 had a clinical outcome identical to that of ‘PET negative’ (score 1–2) pts and ROC analysis suggested that moving the cut-point for the definition of CR from the MBP to the liver uptake, will increase specificity while maintaining sensitivity. Indeed, defining the response using the liver uptake as a cutpoint is a better predictor for both PFS (p Conclusions. Using the MBP cut-point, the PET-positive rate (Deauville score>2) after R-CHT in PMLBCL was higher (53%) than in DLBCL. However, more than 90% of pts are projected to be alive and progression-free at 5 years post treatment and a negative PET/CT after R-CHT is significantly associated with a longer PFS. Pts with score 4 and 5 had a significantly worse PFS and OS. Hence, the liver uptake may represent a more appropriate cut-point than MBP to identify poor-risk pts who may need early intensification of therapy. The frequent use of IFRT in this study precludes any clear conclusion about its role, but the new IELSG-37 randomized trial will assess whether mediastinal irradiation can be safely omitted in PMLBCL pts achieving a CR after R-CHT. Disclosures: No relevant conflicts of interest to declare.